Brake shoe



Feb. 9, 1932,. T, P, CHASE 1,844,461

BRAKE SHOE Filed Jan. 2l, 1929 Wear/f gaie Patented Feb. 9, 1932 ALUNITED STATES PATENT OFFICE IHERON I. CHASE, OF DETROIT, MICHIGAN, ASSIGNOR TO GENERAL MOTORS RESEARCH CORPORATION, F DETROIT, MICHIGAN, A CORPORATION OF DELAWARE BRAKE SHOE Application led January 21, 1929. Serial No. 333,975.'-

This invention relates to brakes and has been designed more especially for vehicle brakes although its use in other relations Wherever surfaces are to be brought into frictional contact will be obvious.

An object of the invention is to condition the brake drum surface or the surface of one of 'two rictional engaging members and thereby prevent scoring. Another object'is to increase the efficiency and life of the Jfrictional engaging members. Other objects and advantages will be readily appreciated from the following description.

ln its broader aspects the invention consists in the rubbing against one of the frictional engaging surfaces of lead or of an alloy containing lead, an alloy of lead and copper, for example, being quite satisfactory. This rubbing of the surface of the rotating member, for example, the drum of a vehicle wheel brake, may be accomplished in various ways. Some of these ways are illustrated by the drawings accompanying this description.

In the drawings, Fig. 1 is a section through a vehicle brake drum showing the shoes in elevation, this ligure also showing one method by which the drum surface is conditioned. Fig. 2 is a side elevation of a brake shoe removed from the drum, the shoe being modied so that in action it may carry out the purpose of this invention. 4 i

Fig. 3 is a plan View of the' shoe shown in Fig. 2.

Fig. 4 is a side elevation of a shoe showing a slightly different embodiment of the invention.

Fig. 5 is a plan view of the brake shoe shown in Fig. 4.

Fig. 6 is a section on line 6 6 of Fig. 4.

Fig. 7 is a plan view of another 'form which the invention may take.

Fig. 8 is a section on line 8-8 of Fig. 7.

Fig. 9 is a side view of still another form of brake shoe and Fig. 10 illustrates a still further modication 1n side view.

gagement with the drum to check the rotation of the drum and the wheel. Since the invention is not concerned with the wheel and aXle arrangements no further description need be given of these parts.

Within the drum are shown two shoes 17 and 19. These shoes are pivotally anchored to the backing plate at 21 and 23. A cam 25 operates against rockers 27 carried by the shoes to expand the shoes into contact with the 'rotating drum and check its rotation.

The details of the shoes are not a part of this invention. The anchorage and the actuating means are also not a part of this invention and further description of the structure and operation of these parts is not essential. It may be mentioned that in the form shown links connect the shoe 17 with the anchor pin 21.

At some convenient position, preferably adjacent the anchors of the shoes, a yielding spring 31 is secured to the backing plate at 33. This spring has secured to its end a block of lead or of a lead alloy such as lead and copper. This block is designated by numeral 35. The block is curved on its outer surface to conform to the drum surface as shown and is held by the spring against the drum surface. As the drum rotates, this block of lead or alloy is held resiliently against the drum surface. It is found that the frictional contact between the lead and the drum improves the surface of the drum so that when the shoes 17 and 19 are expanded into contact with the drum a. better brake' action is had,

scoring is avoided and longer life is insured v for the frictional engaging members.

6 The same result may be accomplished in other ways.

In Figs. 2 and 3 is shown a shoe 41 provided with a fabric lining 43. This lining is secured by rivets 45 as usual. The shoe has a number of depressions 44 in which studs of lead or of a lead. alloy 46 are carried, these studs projecting through suitable openings in the lining 43. Any desired number of such studs may be used. It will be observed that the studs are distributed longitudinally and also transversely in such a way that as the shoe engages the drum the whole engag` ing surface of the drum will be in contact with the lead studs. In this form of the invention, it will benoted that the rubbing of -the lead against the drum takes place only when the shoes are in active braking position, differing in this respect from the form shown in Fig. 1 where the lead block 35 is in constant engagement with the drum.

-In Figs. and 6 the lining is shown asin parts 51a and 516. Between these parts and also at the end of each part are blocks of lead v -or lead alloy 52 mounted in recesses 55 of the shoe. These blocks 52 are secured by suitable fastening means 57 as shown in Fig. 6. It will be understood that while the drawings show three such members 52 on each shoe a larger member or smaller member mav be used as as in the case of the studs shown by Fig. 2.

Another form of the invention is illustrated in Figs. 7 and 8. Here the lining 61 is continuous as usual but in place of the usual rivets there may be used lead or lead alloy rivets 63 shaped, for example, as best shown in Fig. 8. 4The surface of thesesoft lead or alloy rivets rubbing against the drum conditions the brake drum surface as before. Here again the distribution of the fastening means is such as to cause the peripheral sur face of the drum to be conditioned by contact with the lead surface.

In Fig. 9 is shown another way in which the inventive idea may be carried out. In this figure the lining 71 which may be of asbestos as usual and either of woven type or molded type has mixed therewith metal in powdered form as clearly indicated by the drawings. It will be understood that this mixture of the metal with the material of the lining is made during the process of manufacture.

In Fig. 10 is shown a form of the inven i i o tion wherein a wire of lead or lead alloy is woven with the asbestos yarn. Here again it will be understood that the wire is incorporated with the material of the lining in the process of manufacture. In this form as in the others as the shoe engages the drum In testimony whereof Iaiiix my signature. b

THERON P. CHASE.

desired. The action is substantially the same 

